Genetic material as a motor: For the first time, scientists have converted the genetic molecule DNA into a nanoscale electric motor. To do this, they assembled several strands of DNA to form a base with a rotor arm. If a voltage is now applied, the DNA rotor begins to move and rotate in one direction, as the researchers report in the journal “Nature”. The new nano-electric motor opens up the possibility of driving nano-processes and chemical reactions in new ways.
For several centuries, engines have been relieving humanity of work. Their main task is to convert various forms of energy into motion – even on the smallest scale. There are now nanomotors that are only one nanometer in size and others that have been built from the DNA genetic material molecule. So far, however, these have only been able to generate motion from chemical energy, not electrical energy.
Origami with genetic material molecules
A team led by first author Anna-Katharina Pumm from the Technical University of Munich has now built a nanoscale electric motor out of DNA. To assemble the molecular motor, the scientists used something called DNA origami. With this method of construction, several long single strands of genetic material serve as the basic structure, to which other sections of complementary DNA then attach. The sequences of the molecules are chosen such that the desired structures result from the tethers and folds.
“We have been working with this method for many years and can now develop very precise and complex objects such as molecular switches and hollow bodies capable of capturing viruses. If you put the DNA strands with the corresponding sequences in solution, objects fit together,” says lead author Hendrik Dietz of the Technical University of Munich.
Base, Platform, Rotor
The researchers used origami technology to build three components for their new DNA engine. They are based on a base about 40 nanometers high, which is anchored to a glass plate using polyethylene glycol. A 13 nanometer thick DNA platform is then mounted on the foot, connecting the base to a 500 nanometer long DNA rotor arm. The structure of the intermediate element is responsible for the function of the engine.
Basically, the DNA engine works like a kind of ratchet. Obstacles in the intermediate platform limit the rotation of the rotatable mounted arm. Without specific energy input, the rotor moves randomly and uncontrollably, as it is influenced only by collisions with solvent molecules. However, as soon as an alternating voltage is applied via two electrodes, the arm rotates purposefully and continuously in the desired direction. Finally, scientists can influence the speed and direction of rotation via the direction of the field and the frequency and magnitude of the voltage.
“Technically unparalleled skills”
“The new engine has unrivaled mechanical capabilities,” says co-author Ramin Golestanian of the Max Planck Institute for Dynamics and Self-Organization in Göttingen. “It can reach torques of the order of 10 piconewtons per nanometer. And it can generate more energy per second than is released by splitting two molecules of ATP.
The scientists hope that the engine they have developed will take on specific technical tasks in the future, such as converting electrical energy into chemical energy. “We could potentially use it to trigger chemical reactions in the direction of ATP production. For example, surfaces could be densely covered with such engines,” says Dietz. “Then you add raw materials, apply a small AC voltage, and the motors produce the desired chemical compound.” (Nature, 2022; doi: 10.1038/s41586-022-04910-y)
Source: Technical University of Munich
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